app

commit edea0bec57287f95dc080863ea0076eef9ad690a
parent 99c644eb61fc8cb0c987318c5bafa61200e425ef
Author: triesap <triesap@radroots.dev>
Date:   Wed, 21 Jan 2026 19:54:11 +0000

ui: add event composition helpers

- add compose helpers with default-prevented predicate

- add unchecked compose helper for simple handlers

- add unit tests for ordering and prevention

- export event helpers from ui-core

Diffstat:
A
crates/ui-core/src/event.rs
 | 
83
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
crates/ui-core/src/lib.rs
 | 
5
+++++

2 files changed, 88 insertions(+), 0 deletions(-)
diff --git a/crates/ui-core/src/event.rs b/crates/ui-core/src/event.rs
@@ -0,0 +1,83 @@
+pub fn radroots_app_ui_compose_event_handlers<T, A, B, P>(
+    mut first: Option<A>,
+    mut second: Option<B>,
+    mut is_prevented: P,
+) -> impl FnMut(&T)
+where
+    A: FnMut(&T),
+    B: FnMut(&T),
+    P: FnMut(&T) -> bool,
+{
+    move |event| {
+        if let Some(handler) = first.as_mut() {
+            handler(event);
+        }
+        if is_prevented(event) {
+            return;
+        }
+        if let Some(handler) = second.as_mut() {
+            handler(event);
+        }
+    }
+}
+
+pub fn radroots_app_ui_compose_event_handlers_unchecked<T, A, B>(
+    first: Option<A>,
+    second: Option<B>,
+) -> impl FnMut(&T)
+where
+    A: FnMut(&T),
+    B: FnMut(&T),
+{
+    radroots_app_ui_compose_event_handlers(first, second, |_| false)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{
+        radroots_app_ui_compose_event_handlers,
+        radroots_app_ui_compose_event_handlers_unchecked,
+    };
+
+    #[derive(Default)]
+    struct TestEvent {
+        calls: core::cell::Cell<usize>,
+        prevented: core::cell::Cell<bool>,
+    }
+
+    impl TestEvent {
+        fn mark_called(&self) {
+            self.calls.set(self.calls.get() + 1);
+        }
+
+        fn prevent(&self) {
+            self.prevented.set(true);
+        }
+    }
+
+    #[test]
+    fn compose_calls_handlers_in_order() {
+        let event = TestEvent::default();
+        let mut handler = radroots_app_ui_compose_event_handlers_unchecked(
+            Some(|evt: &TestEvent| evt.mark_called()),
+            Some(|evt: &TestEvent| evt.mark_called()),
+        );
+        handler(&event);
+        assert_eq!(event.calls.get(), 2);
+    }
+
+    #[test]
+    fn compose_skips_second_when_prevented() {
+        let event = TestEvent::default();
+        let mut handler = radroots_app_ui_compose_event_handlers(
+            Some(|evt: &TestEvent| {
+                evt.mark_called();
+                evt.prevent();
+            }),
+            Some(|evt: &TestEvent| evt.mark_called()),
+            |evt: &TestEvent| evt.prevented.get(),
+        );
+        handler(&event);
+        assert_eq!(event.calls.get(), 1);
+    }
+}
diff --git a/crates/ui-core/src/lib.rs b/crates/ui-core/src/lib.rs
@@ -4,5 +4,10 @@
 extern crate alloc;
 
 mod id;
+mod event;
 
+pub use event::{
+    radroots_app_ui_compose_event_handlers,
+    radroots_app_ui_compose_event_handlers_unchecked,
+};
 pub use id::{RadrootsAppUiId, RadrootsAppUiIdSequence};